The present invention relates generally to wireless communication and, in particular, to an interference-efficient method for providing CDMA services.
The CDMA 2000 standard provides for two types of channels, a fundamental channel (FCH), which is the only type of channel for providing voice services, and a dedicated control channel (DCCH). For a DCCH, full frames of data must be transmitted. That is, if less than a full frame of bits are to be transmitted, then the frame must filled (padded) with unneeded bits in order to send a full frame. For a DCCH, when there is no data to send, only power control information is sent at approximately 800 bits per second rate.
For a FCH, full, half, eighth (and possibly quarter) rate frames of data may be transmitted. That is, the frame rate is generally the lowest rate frame that is large enough to carry the payload. The rest of the frame is then filled (padded) with unneeded bits in order to send the frame rate selected. For a FCH channel, when there is no data to send, power control information and an eighth rate frame is sent. The transmission of this basically empty frame reduces overall system capacity by increasing the level of RF interference in the system. Thus, reducing the RF impact of these eighth rate frames on the system would recover some lost system capacity. Therefore, a need exists for an interference-efficient method and apparatus to provide CDMA services to remote units.